1. Field of the Invention
This invention relates to lead-acid cells and batteries, and, more particularly, to a pedestal and cell tray assembly for housing such cells and batteries.
2. Description of the Prior Art
Stationary batteries are specifically designed for float applications, that is, as standby power in the event of a power failure. Stationary batteries are usually maintained at a full-state-of-charge and in a ready-to-use condition typically by floating at a constant preset voltage. Standby batteries are used for standby or operational power in the communications field, utilities, for emergency lighting in commercial buildings and uninterruptible power supplies.
Uninterruptible power supplies are systems that back-up computers and communication networks. Sealed lead-acid cells and/or batteries may comprise the power source. The uninterruptible power source allows for the orderly shut down of computers when there is a sudden interruption in the primary electrical source, such as during a power outage and provides back-up power for communications networks. The uninterruptible power supply also will accommodate short, or intermittent, losses in power. When there is a power interruption, the batteries in the uninterruptible power system can be subject to rapid discharge.
The sealed lead-acid stationary cells and/or batteries used for industrial applications where the power requirements are high and quite demanding are typically comprised of from several to a large number of individual sealed lead-acid cells connected to one another to form a battery with the desired capacity and power requirements. The individual sealed lead-acid cells may be connected in series, in parallel or in suitable combinations of series and parallel to form a battery with the desired capacity and power requirements. External connections are typically made between the negative and positive terminal posts of the respective cells.
The weight of lead-acid cells used for such high rate applications can vary considerably. However, each individual cell may, for example, weigh from about 30 to 60 pounds or more.
Because of space considerations, these large capacity cells need to be placed on racks, cabinets or the like in an attempt to minimize the space requirements. Height limitations in some locations also present a problem for providing racks for the number of cells required, given the available floor space. A complicating factor is that, due to the weight of the cells, the cell rack or cabinet must be extremely sturdy in construction and stable in use. Still further, for Zone 4 applications, i.e., locations where high seismic conditions can occur, there are even further stringent requirements that must be met to insure that the cells are adequately secured in the racks should such high seismic conditions occur.
To satisfy these diverse requirements, the cell tray racks and trays currently being used, insofar as it can be ascertained, all utilize metal base supports. While such supports adequately accommodate the weight of the cells and may perhaps satisfy the stringent requirements of UBC Zone 4 applications (i.e., satisfy the requirements that the cells are adequately secured under defined high seismic conditions), there are substantial disadvantages. Such metal base supports allow essentially no flexibility in the case of an uneven mounting surface, often the floor of a building, since the support typically will not bend enough to follow the contour of an uneven mounting surface. Further, to satisfy the load and seismic requirements, such metal supports have been both relatively heavy as well as being costly, often being made of relatively expensive metals such as steel.
Additionally, and importantly, such metal base supports do not provide any electrical insulation from ground in the event of the short circuiting of the cell tray system being accommodated in the rack or tray. This is particularly significant in applications requiring relatively high voltages. Accordingly, this important safety feature has been either ignored in such existing metal base supports and racks or supplemental means have been utilized in an attempt to satisfactorily provide electrical insulation from ground. Such solutions tend to be complicated and the overall cost considerations are often relatively expensive.
The pedestal or base supports in use likewise pose inventory and manufacturing complications. Thus, insofar as applicant is aware, the pedestals in use lack universality. It is therefore the case that different sized cells or batteries have used racks with different pedestals.
It is accordingly a principal object of the present invention to provide a pedestal support and tray assembly capable of housing cells and/or batteries used for standby applications which minimizes, if not eliminates, short circuit problems by providing an electrical insulation from ground while satisfying the diverse requirements required for accommodating cells and batteries for standby applications.
A further object is to provide a pedestal and tray assembly which is cost-effective and which can be readily manufactured.
Another object of the present invention lies in the provision of such a system which satisfies the requirements for use in high seismic areas, specifically UBC Zone 4 applications.
Yet another object of the present invention provides pedestals that can be readily attached and removed from a cell tray assembly so as to provide enhanced flexibility in use and may be used with a wide variety of cells and batteries.
These and other objects and advantages of the present invention will be apparent from the following descriptions and drawings. While the present invention may be used with any batteries or cells that satisfy the requirements of the particular application, it will be described herein in conjunction with sealed lead-acid cells (often termed "VRLA" cells, i.e., valve-regulated lead-acid).